JavaScript before leaving the page

Question

I want to make a confirmation before user leaving the page. If he says ok then it would redirect to new page or cancel to leave. I tried to make it with onunload

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Answer 1

You can use the following one-liner to always ask the user before leaving the page.

window.onbeforeunload = s => "";

To ask the user when something on the page has been modified, see this answer.